5 Best Under Sink Water Filters for Well Water (October 2023)

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After testing countless undercounter filtration systems, our experts determined these to be the best for use with well water in 2023.

Hey, well owner! Welcome to our best under-sink water filter for well water guide.

If you’re looking for a capable, fantastic-value under-sink water filter that can effectively treat your well water drinking supply, you’ve come to the right place. We’ve tried and tested dozens of under-sink filters with water from our own private wells across the US.

Feel free to buy a water filter on a whim that’s a nightmare to install, doesn’t last as long as it’s advertised to, and removes virtually none of the contaminants you bought it to remove. But we strongly recommend buying a system that you can truly feel pleased to have invested in – one that exceeds your expectations in all aspects of performance, durability, and ease of use.

#1 is our favorite, but #3 is the best system for well water with bacteria, and #4 is best for small budgets.

In this guide, we’ll share:

  • Which 5 under-sink well water filters are worth spending your money on in 2023
  • How we researched, tested, and compared the shortlisted products in this guide
  • Everything you need to know to select the best under sink water filter for well water

🥇 Best Under Sink Filter for Well Water

📊 Comparison Chart of Under Sink Filter for Well Water

ProductClearly Filtered Under Sink Filtration System
Clearly Filtered
Under Sink System
Waterdrop G3P800 Under Sink RO System
Waterdrop G3P800
Under Sink RO System
Acuva Arrow 5 UV-LED Water Purifier
Acuva Arrow 5
UV-LED Water Purifier
Epic Smart Shield
Epic Smart Shield
Under-Sink Filter
Home Master TMHP HydroPerfection
Home Master
TMHP HydroPerfection
Ranking1st 2nd3rd4th5th
Contaminants Reduced232+1000+10+70+1000+
Certifications or TestingNSF 42, 53 & 401NSF 58, 372NSF 55, 372NSF 42, 53, 401NSF 51
Filter Life2,000 gallons6, 12, 24 months4,000 gallons651 gallons2,000 gallons
Flow Rate1.25 GPM800 GPD1.30 GPM1.25 GPM1 GPM
WarrantyLifetime1 year2 yearsLifetime5 years
Annual Cost$396-$440~$145~$120~$130

⭐ Reviews – Best Under Sink Filter for Well Water 2023

Key Features:

  • Targets well water contaminants – The Clearly Filtered Under Sink Filtration System has got your back regardless of what your well water contains. This capable under-sink system reduces the likes of heavy metals, pesticides, arsenic, and much more.
  • Reduces more than 200 contaminants – This under-sink water filter doesn’t only cover you against the typical well water impurities; it reduces virtually everything. You can be almost certain that even trace contaminants in your water will be targeted by this system.
  • Privately tested to NSF Standards – While this Clearly Filtered model is missing an official NSF certification, it has been privately tested to NSF Standards 42, 53, and 401. Clearly Filtered is one of the few transparent manufacturers and shares its test results online for anyone to see.
  • Effective three-stage filtration process – The filter stages involved in this under-sink water filter are granular activated carbon media (for chlorine and chemical reduction), a special blend (for radiological elements and chromium), and an undisclosed filter (likely activated alumina, as it can reduce fluoride).

Best For: Anyone with the cash to splash on a premium under-sink water filter that reduces more well water contaminants than any other under-sink system on the market.


  • We love that this system tackles so many impurities, including those commonly found in a private well. Of all the under sink filters we tested, our water quality was the most greatly improved with the Clearly Filtered Under Sink Filtration System.
  • We’re impressed with the durability of this system. The stainless steel unit and premium-quality outlet ports are built to last, and the filters themselves last for up to one year before they need to be changed.
  • The 30-day money-back guarantee and lifetime warranty are incredibly reassuring. You can buy this under-sink water filter at no risk whatsoever.


  • If your well water is high in sediment, the filter stages in this system will likely become clogged quickly. Sediment pre-filtration is recommended in this case.
  • This Clearly Filtered system is one of the most expensive on the market. We think it’s a great value for money, but it might still be out of your budget.

Read the Full Review: 2023 Clearly Filtered Under Sink Water Filter Review

Key Features:

  • Removes 1,000+ contaminants – If you want purified water from your kitchen faucet, the Waterdrop G3P800 is your answer. This innovative RO system removes more than 1,000 contaminants, including all the contaminants that are commonly found in well water.
  • Seven thorough filtration stages – Most RO units have three or four filter stages, but the G3P800 doesn’t stop there. For the most thorough well water treatment, this unit consists of seven filter stages: two PP cotton layers, an activated carbon block layer, a scale inhibitor layer, a reverse osmosis membrane layer, a post-activated carbon block layer, and a UV sterilizer.
  • Multiple intelligent features – The G3P800’s high-tech design is above and beyond anything offered by its competitors. There’s a TDS indicator, a filter life indicator, an LED chip for microorganism removal, and a malfunction alert.

Best For: Anyone who’s keen to purify their well water with the best, most capable, space-saving, high-tech under-sink reverse osmosis system available today.


  • The G3P800 is one of the most user-friendly under-sink reverse osmosis systems we’ve used, and we can’t get enough of its innovative features that take the user experience to the next level.
  • We were blown away by just how many contaminants this small, compact unit can remove – including all the most common well water impurities.
  • In our testing, this Waterdrop model wasted far less water than any of the other reverse osmosis systems we’ve tried. The manufacturer says that traditional RO systems waste 12 times the amount of water that the G3P800 wastes.


  • While the Waterdrop G3P800 can be used as it is with city water, there are different rules for well water. As in all RO systems, raw well water would clog the G3P800’s membrane with iron, hardness minerals, and harmful pathogens. Pre-treatment, such as shock chlorination and sediment filtration, are required for this system.
  • At just over $1,000 the G3P800 isn’t cheap for an under-sink water filter. The price is worth it, but still too expensive for some people.

Read the Full Review: Waterdrop G3 P800 Reverse Osmosis System Review

Key Features:

  • Best UV purification – We’ve done the research, and we can confirm that there are no other point of use filters that offer the same quality of UV filtration as the Acuva Arrow. 99.9999% of viruses and bacteria elimination is as good as it gets.
  • Includes advanced pre-filter – The UV purifier might be the star of the show, but this Acuva model also comes with an advanced pre-filter, which removes the likes of fluoride, mercury, chromium-6, asbestos, turbidity, and poor tastes and odors.
  • Compact, all-in-one system – Everything you need to filter your well water with the Acuva Arrow 5 UV-LED Water Purifier comes in a single compact box, so it’s easy to install and doesn’t take up too much under-sink space.

Best For: Anyone with well water that’s prone to microbiological contamination, who wants a compact, under-sink system that guarantees safe drinking water – and, as a bonus, also removes heavy metals.


  • The Acuva Arrow’s impressive pathogen elimination is incredibly reassuring, and we felt in safe hands with this system.
  • We’re impressed with the system’s 900,000-liter, or 10-year, lifespan, and the unit’s aluminum casing feels high quality and durable. The 2-year warranty is reassuring, too.
  • It’s good to have the option of buying a smart faucet with the system. We bought it, and recommend that you buy it too, as it has a self-cleaning feature and lights up to let you know that the system is working correctly.


  • This system plays multiple roles in one and eliminates the need for a separate UV purifier at your home’s point of entry. This makes it expensive, and some people might be put off by the price.
  • The main job of the Acuva Arrow is to kill pathogens. Although it also targets common well water heavy metals and minerals, it won’t eliminate all the contaminants in your well.

Key Features:

  • Greatly reduces 70+ contaminants – The Epic Smart Shield removes a lot of contaminants for such a small device. This system improves your well water quality by removing everything from pathogens to heavy metals, chemicals like chromium-6, fluoride, and more.
  • Third-party certified to NSF Standards – A huge bonus of this Epic filter is that it has been independently certified to NSF/ANSI Standards 43, 53, 401 – and helpfully, the manufacturer has shared the test results online for us to see.
  • Coconut shell activated carbon filter – The Smart Shield uses one of the most reliable filter materials: coconut shell activated carbon. This grabs contaminants out of the water using adsorption.

Best For: Anyone with a small budget who wants to pay a fair price for a capable under-sink water filter for well water, offered by a reputable brand.


  • At just over $100, we think the Epic Smart Shield is a steal. Sometimes, low cost means poor quality, but our testing proved that this Epic filter is well made and lives up to the manufacturer’s claims.
  • This filter is one of the easiest under-sink water filters we’ve ever installed. The quick-connect fittings and inline design allow you to hook the filter up to your cold water line in a matter of minutes.
  • We’re pleased with the filter’s 12-month lifespan. That’s six months longer than most carbon filter cartridges last.


  • Epic doesn’t offer a trial period or money-back guarantee for this water filter.
  • Our water flow rate dropped ever so slightly after installing this filter. It shouldn’t be enough to cause issues, but it’s still worth being aware of.

Read the Full Review: Epic Water Filters Smart Shield Under Sink System Review

Key Features:

  • Thorough contaminant removal – The Home Master TMHP HydroPerfection offers the high performance you’d expect from a reverse osmosis system, removing up to 99.9% of more than 1,000 contaminants including iron, chemicals, heavy metals, hydrogen sulfide, and TDS, and sterilizing 99.99% of microorganisms.
  • Tailored upgrades – This Home Master model is one of the only reverse osmosis systems that you can tailor to your needs and tastes. There are 19 different faucets to choose from (including a no faucet option), and five different tank sizes. You can also upgrade the RO membrane to one that’s suitable for hard water, and buy an optional refrigerator connection kit and antimicrobial tubing.
  • Good warranty and support – You’re backed by a 5-year warranty when you buy this system, with US technical support. Home Master also offers a 30-day satisfaction guarantee, so you can buy this product risk-free.

Best For: Anyone who likes the idea of a traditional tank-based reverse osmosis filter that can be altered into a system that’s perfect for your needs.


  • The Home Master TMHP HydroPerfection has got you covered against all the most common well water contaminants, from heavy metals to microorganisms.
  • This model has an efficient 1:1 water waste ratio, and we noticed a huge reduction in water use compared to similar RO filters.
  • We love how many tailored options there are for this reverse osmosis filtration system – you can really make it your own.


  • Like all reverse osmosis systems, this Home Master model can’t be used to treat well water without pre-treatment. The high sediment content of raw well water would damage the RO membrane within a matter of months.
  • The Home Master TMHP HydroPerfection has a clunky design and takes up a lot of space, so it’s not ideal as a space-saving under-sink option.

🕵️ Our Research

This section of the guide shares everything you need to know about the under-sink water filtration systems for well water, including the types of under-sink water filters available, which common well water contaminants can be tackled by under-sink filters, who should buy an under-sink system, and more.

🤔 What are the Common Well Water Contaminants?

According to the EPA, the most common categories of well water contaminants are:

  • Microorganisms – Like bacteria, viruses, and parasites
  • Nitrate and nitrite
  • Heavy metals – Like lead, arsenic, copper, selenium, and chromium
  • Radionuclides – Like radium and uranium
  • Organic chemicals – Like pharmaceuticals, pesticides, and solvents
  • Fluoride

Most of these contaminants enter well water through surface runoff or from seeping through the soil into the aquifer. Some well water impurities occur naturally in the environment, while others are caused by industrial and agricultural pollution, or poor waste disposal.

We assume you know quite a lot about well water contamination if you’re reading this guide, but if you are looking for more information on the subject, check out this guide.

Water quality map
Source: United States Geological Survey

🚰 Do I Need a Water Filter That Removes Well Water Contaminants?

If you have a private well, your water doesn’t get treated by your local authority, so it’s delivered to your home in a raw, untreated form.

That means you do need to treat your water before you can use it, and an under-sink water filter for well water will be hugely beneficial to you.

Alongside an under-sink filtration system, you might also need a form of pre-treatment, like a sediment filter or a water softener, depending on your water quality and what type of filter you buy.

🙋‍♀️ Who This Guide is For

This guide is for people who are specifically looking for a well water treatment solution for their drinking water only. You’ll get value from this guide if:

  • Your budget is flexible. We have budget-friendly and splurge options on this list, though one thing always remains – the value for money is there.
  • You just want to treat your drinking water. You don’t mind using contaminated well water throughout your home, but you want to drink clean, filtered water from your kitchen faucet.
  • You’re open to different options. Though you know you want an under-sink water filter, you’re happy to consider the different types of filters shared in this guide.
  • You want to avoid untrustworthy manufacturers. We can help you buy a product that’s recommended by customers and water treatment professionals alike.

🧪 How We Tested

Our original testing process involved carrying out before-and-after water tests with Tap Score laboratory testing. However, it quickly became apparent that our own well water was pretty mild compared to the test waters used in official industry testing. We realized that our results were limited, and didn’t tell us much about a filter’s true capabilities.

For this reason, our testing now focuses solely on the user-friendliness of an under-sink filtration system, and how it performs on a day-to-day basis. We combine our invaluable real-life user experience with official testing data from the NSF, the WQA, and third-party testing organizations. This gives us the best understanding of how different filters compare across the board.

Tap score water test report

📊 How We Chose

This guide is solely for under-sink water filter systems that are capable of removing well water contaminants. Because of this, our search was fairly focused, and we had a relatively small pool of products to compare.

We chose the filters on this list based on their ability to remove common well water contaminants, the quality of their components, their customer feedback, and their value for money.

Contaminant Removal Abilities

First and foremost, we know that if you’re looking for an under-sink water filter system for well water, you expect it to remove the common contaminants in your well water supply.

We began our research with a list of the common well water contaminants, as defined by the EPA, and looked at product descriptions and test results (and, if information wasn’t available, spoke directly to manufacturers) to tick these contaminants off our list. The filters that removed the most contaminants made it into our group of shortlisted products.

Testing water quality

Component Quality & Durability

We understand that there’s nothing worse than buying a so-called durable water filter system that lets you down after less than a year of use. That’s why testing our shortlisted filters was so important to us.

We didn’t want to take the manufacturer’s word for it; we wanted to see with our own eyes and feel with our own hands to confirm that a water filter was good-quality and built to last. We also read customer reviews to learn about a filter’s long-term durability.

This helped us to narrow down our choices, eliminating the products that didn’t meet our expectations.

Customer Feedback

Customer feedback is an invaluable tool when you’re researching the best water filter systems. From reading hundreds of customer reviews, we were able to compare the overall user experience for all our shortlisted under-sink water filters.

Customer feedback gives a clear impression of how a water filter lives up to customer standards and expectations. We avoided the under-sink water filters that received repeatedly negative criticism for the same reasons, such as poor-quality design or subpar filtration.

Person checking user reviews

Value for Money

Value for money was perhaps our most important consideration of all when choosing under-sink well water filters, as it combines all the most important features of a water filter and answers the question: “Is it worth the price we’re paying?”

We know that customers work hard to earn their money, and they want to be certain that they’re spending it wisely on a product that serves them well for years, or even decades. That’s why we didn’t focus on price in our search for the best under-sink well water filters – we focused on overall value.

The under-sink water filters on this list are the best value for money systems you can buy today, offering exceptional features and performance aspects that make them well worth their price.

🧾 Buyer’s Guide

Under-sink well water filters are units that are designed to filter common well water contaminants and deliver filtered drinking water directly out of your faucet. These systems are hooked up to your cold water line and are powered by your home’s water pressure.

This section of the guide covers all the important information about buying a well water filter system for under your kitchen sink.

Types of Under-Sink Filter Systems for Well Water

There are three main types of under-sink water filtration systems for well water:

Single-Stage Systems

Single-stage water filtration systems consist of a single filter and are typically the cheapest and most compact options. Often, these filters combine more than one filtration process into a single cartridge. A carbon filter is usually the main media, and may be combined with sediment filter media, or specialized media, like KDF or activated alumina.

Epic water filters smart shield installation

Multi-Stage Systems

Multi-stage under-sink systems consist of two, three, four, or more stages. Usually, these filter stages include dedicated sediment and carbon filters, post or polishing filters, and specialized filters, like activated alumina. These filters offer more thorough, dedicated filtration, but they have a bigger effect on flow rate than single-stage units, and making filter replacements is more expensive. The installation and maintenance process tends to be a bit trickier with these systems, too.

RO Systems

Reverse osmosis (RO) under-sink systems are the best under-sink water treatment option for highly contaminated water. RO units combine a sediment and carbon filter with a semi-permeable membrane to remove virtually all contaminants from water, and often come with a separate faucet to prevent metal from leaching into the purified drinking water. The downside of RO is that you’ll need to pre-treat your well water supply with a sediment filter or a water softener to prevent damage to the RO membrane.

Tank-based ro system

Pros and Cons of Under-sink Filtration Systems

Even the best under-sink water filters have their setbacks. Let’s look at the advantages and disadvantages of buying an under-counter water filter system to treat your well water:


  • An under-counter water filtration system can remove an impressive host of harmful contaminants, from microbiological impurities to heavy metals.
  • This type of water filter should noticeably improve the taste and smell of your tap water.
  • If your home’s water pressure is adequate, an under-sink filter shouldn’t affect your flow rate.
  • Under-sink systems are budget-friendly compared to whole-home water filters.
  • Under-sink systems are more convenient than countertop filters because they provide filtered tap water on demand.
  • Most under-sink systems are suitable for DIY installation.


  • The filter capacity of an under-the-sink water filtration system is fairly limited. You’ll need to buy a filter replacement every 6-12 months.
  • This type of filter only delivers filtered tap water via a single cold water feed line to one faucet.
  • If your water pressure is low, you might need to install an electric pump before your filter to prevent it from reducing your flow rate.
  • If your well water quality is poor, you might need a pre-treatment filter as well as an under-counter water filtration system.
Clearly filtered under sink filter cold water line

Buying an Under-Sink Filtration System for Well Water: What to Consider

Here, you’ll learn about everything you should consider when buying an under-sink water filter system to treat your well water.

Your Water Quality & Pre-Treatment

Well water is rarely suitable for drinking without some form of treatment. It’s important to test your water annually to check for new contaminants, and treat your tap water accordingly.

The quality of your water will determine which under-sink filter system is best suited to your needs. For instance, if your water is prone to microbiological contamination, you’ll be best using a system that has a built-in UV filter. Or, if heavy metals are your biggest concern, look for a filter with a proven ability to remove iron, arsenic, lead, and so on.

Your water quality doesn’t only tell you what under-sink filter is best for you, but also gives you knowledge about whether you need a pre-filter. If your water has high sediment, dangerous pathogens, or hardness, you may need to install a sediment pre-filter, a UV purifier, or a water softener at your point of entry.

This is especially the case if you plan to buy a reverse osmosis system. No matter what your water quality, you need proper pre-treatment for an RO filter, and you should never use RO filters as a primary treatment for well water.

Your water parameters are also important to consider. If your water is too acidic (a common well water trait), it may spoil the filter media or cause the filter to be ineffective. In this case, pre-treatment is also recommended to alkalize your water.

Sediment pre-filter

Your Budget

Once you know what your water contains, your budget is the place to start.

Consider how much money you can afford to spend upfront on a water filter. If you can’t decide on a figure, a good rule is to ask yourself whether you could afford to pay for a system twice. If you couldn’t, your budget is probably too high.

You can find a highly capable under-sink well water filter for as little as $100, but the truly exceptional filters start at $500. Remember you’ll need to pay for annual maintenance, too, including the cost of replacement filters. Thankfully, this price is much cheaper, at about $100-$200 per year.

Learn all about the Average Cost for Installing an Under-Sink Water Filter 👈

Testing and Certifications

From a customer’s perspective, an official NSF certification is the best proof of a filter’s contaminant removal ability. The NSF is an independent testing and certification organization that all water filter manufacturers can use to test their products. NSF certifications to look for in under-sink filters for well water are:

  • NSF 53, for contaminants with health effects, like lead, giardia, and VOCs.
  • NSF 58, for reverse osmosis systems that can remove health-concerning contaminants.
  • NSF Standard P231, for filters that can reduce microbiological contaminants, like viruses, cysts, and bacteria.
  • NSF 401, for filters that can remove emerging contaminants, like pharmaceuticals, some pesticides, and chemicals like BPA.

Although NSF certifications are a mark of reassurance for customers, we wouldn’t recommend only looking at filters that are officially certified. This will narrow your choices massively because some manufacturers choose not to get their products certified by the NSF.

Instead, look at filters that have some form of proof of performance, such as an online datasheet displaying results from third-party testing.

Number of Filter Stages

Buying a multi-stage under-sink filter isn’t essential. However, the more stages your filtration system has, the more varied filter media the water will come into contact with, and the bigger the variety of contaminants that are removed.

Generally, multi-stage water filters are more expensive than a single-stage under-sink water filtration system. However, if you’re looking for quality output, we’d recommend a system with at least two separate stages.

Nsf logo

Filtration Process

There are a whole host of filtration processes that can be used in under-sink water filters. These include:

  • Activated carbon/adsorption filtration, for improving water’s taste and odor
  • RO membranes, which eliminate thousands of impurities
  • UV light, which purifies water and kills microbiological contaminants
  • Specialist resins and media, like activated alumina, KDF and ion exchange, which remove everything from heavy metals to fluoride, nitrite, and arsenic.

Different filtration methods remove different contaminants and have different lifespans. Ideally, find an under-sink water filter system that combines several of these methods to remove a broader range of impurities.

Flow Rate and Water Pressure

The flow rate and water pressure of a filter are a measure of the speed and output of water from the system. The better a system’s flow rate, the faster you’ll get access to filtered water.

Before installing a water filter system under your sink, your faucet should deliver a flow rate of about 1.5 to 2 gallons per minute. After installing a filtration system, your flow rate will likely drop to about 0.5 to 1.5 gallons per minute. The more stages the filter has, the slower the flow rate.

It’s common for water pressure to fluctuate in homes with private wells. Make sure your home has a water pressure of at least 60 PSI to deliver a strong enough flow of water to pass all the way through a multi-stage filtration system.

There’s no avoiding reduced flow rate from installing an under-sink water filter system, and as long as your water pressure is adequate, this shouldn’t be too disruptive.

Low water flow

Filter Lifespan

On average, the filters in an under-sink filter system last for 6-24 months. The lifespans of the filters in your chosen system will affect how often you need to buy replacement filters.

If maintenance isn’t your thing, look for filters that last at least 12 months. It’s likely that you’ll need to pay more upfront for this privilege.

When you’re still comparing products, estimate how many filter replacements you’ll need to make per year, and the average cost of these replacements. It might be worth spending a bit more upfront on a filter that requires fewer filter changes, therefore costing less in the long run.

Available Space

It’s important to carefully measure your available space and compare this to any water filter you plan to buy. The last thing you want is to have to send back a filter because it’s too tall or bulky to fit in your cabinet.

If you’re short of space, bulky tank-based reverse osmosis water filters are probably out of the question. Luckily, many under-sink water filters are designed to be as compact and space-saving as possible. Inline under-sink filters take up the least space.

Measuring under sink space

Installation and Maintenance

Most under-sink water filters nowadays are advertised as being easy to install, even for people who don’t consider themselves DIY experts. But how true is this?

If you can follow detailed instructions and you have plenty of patience, you should be able to install any of the best under-sink water filters on this list.

When it comes to maintenance, most under-sink filter systems just need filter changes. The frequency of maintenance depends on the type of system you own, and how long the filters last. Look for filtration systems that are easy to maintain – you want filters that can be removed and replaced in a matter of minutes so you don’t end up dreading maintenance or putting it off for too long.

No plumbing experience? Here’s an Easy Step-by-Step Guide on Installing an Under-Sink Water Filter 👈

🧠 Best Under Sink Water Filter for Well Water FAQs

Is well water safe to drink?

Potentially – but even if your well water doesn’t contain pathogens that make you sick, it could still contain a host of other dangerous chemicals and heavy metals. That’s why it’s important to get your water tested at least once a year and treat it as necessary.

water testing with tap score

How do you purify well water for drinking?

The best way to purify well water for drinking is with a reverse osmosis unit – as long as it’s used downstream of a suitable pre-treatment system.

How do you make well water safe to drink?

To make sure your well water is safe to drink, you need either an under-sink filter or a whole house water filter with a UV light. This will kill pathogens in your water and make it suitable for drinking.

Are under-sink filters or whole-house water filters best?

It depends on what you’re looking for. If you just want to filter your drinking water, under-sink filters are easier to install and maintain, and more cost-effective, than a whole house filtration system. However, whole-house systems remove harmful contaminants from your entire home’s water supply, so you can drink, cook with, bathe in, and wash your clothes with filtered water.

Will an under-counter water filter resolve all my well water quality issues?

It depends. Even the best under-sink water filter might be incapable of thoroughly filtering your water if your TDS is high. You may need additional point of entry water treatment to remove pathogens, increase your water’s pH, soften your water, and remove high levels of iron.

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